Today’s students also lack a sense of historical perspective. In the late 1960s and early 1970s, there was an average ofmore than one airplane hijackingper week globally, and those two decades saw hundreds of bombings in the United States by groups ranging from the Ku Klux Klan to the Weather Underground. Indeed, on U.S. soil, both terrorist incidents and fatalities are down in the post-9/11 eracompared with the years before.

However, because 9/11 defines what a terrorist incident can do, a bombing or shooting, especially if done by a Muslim in the name of jihad, looms far larger in the imagination than it did in the past. It is hard for students to picture a country remaining relatively calm about a 1970s-level pace of attacks. It is also difficult for them to imagine a U.S. government with only dozens, not tens of thousands, of counterterrorism officers.